"If the China trade agreement is not resolved in some form before the election, I suspect it will not be good for those running for reelection," Rubenstein said on "Squawk Box."

Talking with reporters Thursday evening, Trump said that U.S. and Chinese officials have been holding "productive" talks. The president said he expects negotiators for both sides to meet as planned next month in Washington, despite 10% U.S. tariffs on $300 billion in additional Chinese imports set to take effect on Sept. 1.

"We don't have to have the most comprehensive China trade agreement of all time in order to have an agreement with China," said Rubenstein, a political independent who says he doesn't give money to either party. "Right now there's uncertainty about China. Give the markets some certainty, even if it's not comprehensive. I think the markets would respond well to it, and I think the Chinese want to make a deal."

Neither country will make "the greatest deal, from their point of view," Rubenstein added. He urged Trump to act in the next few months.

As trade talks had stalled in June, Rubenstein predicted a resolution by the end of the year. In January, however, he indicated that his conversations with U.S. and Chinese officials suggested a trade deal in "the next few months."

"Everyone knows he doesn't accept a bad agreement," said Brady, the ranking Republican on the tax-writing Ways and Means Committee and the driving congressional force behind Trump's 2017 tax cut.

Shortly before Brady's interview on "Squawk Box," Rubenstein stressed that he doesn't believe Trump will make a deal solely to be reelected but to regain economic certainty.

"He has lots of people in his administration that are not worried about the election as much as they're worried about getting a good agreement. I'm sure he wants one, too," Rubenstein said. "The president needs to look at what is doable" in the next four months for economic and market certainty, he added.

Wall Street saw its worst day of the year Wednesday as the 10-year Treasury yield inverted on economic concerns, and briefly went lower than the 2-year yield for the first time since before the 2008 financial crisis and subsequent Great Recession. Such a move has preceded every U.S. recession over the past 50 years, but a recession does not materialize on average for nearly two years.

While saying he does not see an imminent recession, Rubenstein said that if one were to occur, it could mean Trump would become a one-term president.

"For the political people ... the issue is whether or not there's going to be a recession before the next election," he said. "When presidents run for reelection during a recession they tend to lose."

Rubenstein pointed out that only one president since the Civil War was reelected during a recession — William McKinley in 1900.